Re: blocking icmp...
On Sun, May 25, 2003 at 01:09:29PM -0400, Kevin McKinley wrote:
> On Sun, 25 May 2003 07:31:02 -0700
> Paul Johnson <baloo@ursine.dyndns.org> wrote:
> > On Sun, May 25, 2003 at 09:56:07PM +0800, Hanz wrote:
> > > In setting up a firewall will there be any negative side effects if
> > > i block icmp?
> >
> > Well, other than it breaking the TCP/IP standard and making some
> > servers think you don't exist (some ping back), no.
>
> How would declining to answer pings "break the TCP/IP standard"? That's like
> saying if you don't answer the telephone you're breaking the telephone
> standard.
Obviously it only counts if you're sending or receiving other packets.
RFC 1122, a.k.a. STD 3, "Requirements for Internet Hosts --
Communication Layers":
3.2.2.6 Echo Request/Reply: RFC-792
Every host MUST implement an ICMP Echo server function that
receives Echo Requests and sends corresponding Echo Replies.
--
Colin Watson [cjwatson@flatline.org.uk]
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